I22.9

HCC Category Mapping

What This Code Means

A second heart attack within 4 weeks of the first one where the specific location cannot be determined, with ST segment elevation.

Coding Tips

• •Query the provider for the specific wall location of the subsequent MI before using this unspecified code
• •This code should be used only when the location truly cannot be determined from available documentation

Clinical Significance

Subsequent STEMI of unspecified site represents a documentation gap where a recurrent myocardial infarction within 4 weeks is documented but the wall location is not specified. While it still captures the HCC value, this code should prompt the coder to query the provider for site specificity, as electrocardiogram findings typically reveal the involved territory.

Documentation Requirements

• ✓Documentation of a recurrent acute myocardial infarction within 4 weeks
• ✓STEMI pattern confirmed on electrocardiogram
• ✓Re-elevation of cardiac biomarkers
• ✓Evidence that the specific wall location cannot be determined from available records
• ✓Both initial and subsequent myocardial infarction codes must be assigned

Commonly Confused Codes